[SOLVED] SDK version is not compatible with source version - IntelliJ IDEA

[@ibrahimaliyev7294]

When opening my Java project in IntelliJ, my source root often disappears and comes back. The classes I opened close again. How can I solve this problem?
I've checked Invalidate and Restart, I've uninstalled and reinstalled Intellij, I've checked almost everything but still doesn't work.
Please, help me.

[@skilledengg]

Hi @ibrahimaliyev7294, apologies for the delayed response! It sounds like an unusual issue with IntelliJ. Here are a few troubleshooting steps you can try to resolve this:
1️⃣ Check Project Structure and Source Root Configuration:
Go to File > Project Structure > Modules.
Ensure that your source folders are correctly marked as Sources (blue folders) and that your project’s SDK is set properly.
2️⃣ Clear IntelliJ Cache Manually:
Even after using Invalidate Caches / Restart, some cache files may remain. Close IntelliJ and delete the .idea folder in your project directory as well as the workspace.xml file. Then reopen your project.
NOTE (Precautions):
-> Backup (Optional): If you have custom configurations you don't want to lose, back up the .idea folder before deleting it.
-> Reconfigure Post-Deletion: After IntelliJ recreates the .idea folder, you might need to reconfigure things like source root settings, SDK paths, and run/debug configurations.
3️⃣ Verify File Permissions:
Check if your project directory has the correct read/write permissions. Any restrictions could cause IntelliJ to lose track of the source root.
4️⃣ Disable Plugins:
Some third-party plugins might interfere. Disable unnecessary plugins via File > Settings > Plugins and see if the issue persists.
5️⃣ Recreate the Project:
If the issue persists, consider creating a new project and importing your existing files into it. This can help reset any corrupted settings.
If none of these steps work, try checking IntelliJ’s logs (Help > Show Log in Finder/Explorer) for any error messages and share them here.
Also, if you’ve already found a solution in the meantime, it would be awesome if you could share it here so it can help others who might face the same problem. 😊
Let me know if you need further assistance!

[@akshaytaral1378]

error: release version 5 not supported
Language level is invalid or missing in pom.xml. Current project JDK is null. Specify language level in Unknown

[@skilledengg]

Hi @akshaytaral1378, apologies for the delayed response! The error you're encountering ('release version 5 not supported') usually happens when there's a mismatch between the project's language level, the JDK version, and the configuration in your pom.xml file. Here’s how you can resolve it:
1️⃣ Set the Correct JDK Version:
Go to File > Project Structure > Project.
Ensure that the correct JDK is selected under Project SDK.
Set the Project language level to match your JDK version (e.g., 11, 17, or the version you’re using).
2️⃣ Update Your pom.xml:
Add or update the maven-compiler-plugin in the build section of your pom.xml to specify the source and target compatibility:
xml
Copy code

org.apache.maven.plugins
maven-compiler-plugin
3.8.1
11
11

3️⃣ Synchronize the Project:
After updating pom.xml, reimport the Maven project in IntelliJ by clicking the Reload All Maven Projects button in the Maven tool window.
4️⃣ Ensure Language Level is Specified:
Go to File > Project Structure > Modules > Sources.
Set the language level for each module to match your JDK version.
If this doesn’t resolve the issue, please share more details about your setup (like the JDK version and the pom.xml configuration). I’d be happy to help further!
Also, if you’ve already solved the issue, it would be great if you could share the steps you followed to fix it. It might help others facing a similar issue. 😊

[@tejashwareeajbale9364]

Thnak you. You solved my problem

[@skilledengg]

You're welcome! Glad the video helped you.
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